1. Field of the Invention
This invention relates to reversible-cyle closed circuit refrigeration systems and in particular, but not exclusively, to air-conditioning units.
2. Description of the Prior Art
A reversible-cycle closed-circuit refrigeration system generally includes first and second heat exchangers for transferring heat between a refrigerant and first and second fluids respectively, the system being operative selectively to transfer heat from the first fluid to the second and from the second fluid to the first via the refrigerant.
The refrigeration system also includes a compressor which does work on the refrigerant. As a consequence of the heat of compression imparted to the refrigerant, the ratio of the amount of heat transferred through each heat exchanger will depend on the direction of overall heat transfer by the system. As a result, the heat exchangers cannot be designed for optimum operation in both directions of overall heat transfer.
It is therefore an object of the invention to provide an improved reversible-cycle refrigeration system in which the heat exchangers can be operated at maximimum efficiency in both heat transfer directions.